ANALYSIS OF HEAT GENERATION AND INVESTIGATION OF UNDERLYING PHYSICO-CHEMICAL PROCESSES IN LITHIUM-ION BATTERIES

Abstract

The heat losses encountered by Li-ion battery (LIB) can be reduced significantly by identifying and characterising relevant sources because the mitigation strategies for various sources of heat are different. The thesis work focuses on the evaluation of total heat losses encountered while operating commercial LIBs of different chemistries under different current (C) rates. The contribution of reversible and irreversible heat generation to the total heat generation at all C rates is studied. It is followed by the detailed study of internal resistance which contributes to irreversible heat generation and the study of entropic coefficient of individual electrodes which contributes to reversible heat generation. Further, a pseudo 2D (P2D) electrochemical model coupled with a 2D thermal model is employed to understand the mechanisms of heat generation in different battery chemistries. The findings of this thesis would enhance understanding heat generation and aid better design of thermal management systems.